1. Field of the Invention
This invention relates in general to satellite communications, and, in particular, to methods for identifying growth limits of handheld services for mobile satellite communications.
2. Description of Related Art
Communications satellites are in widespread use. The communications satellites are used to deliver television and communications signals around the earth for public, private, and military uses.
The primary design constraints for communications satellites are antenna beam coverage and radiated Radio Frequency (RF) power. These two design constraints are typically thought of to be paramount in the satellite design because they determine which customers on the earth will be able to receive satellite communications service.
Satellite weight is also a factor, because launch vehicles are limited as to how much weight can be placed into orbit. Lower orbits, such as Low Earth Orbit (LEO), and Medium Earth Orbit (MEO), also known as Intermediate Circular Orbit (ICO) do not require as large of a launch vehicle per pound of satellite weight, but LEO and MEO satellites are also weight limited. Since launch costs are large, the satellite must be utilized as much as possible in order to make the satellite commercially viable. If there is not enough usage of the satellite, the satellite manufacturer or the satellite owner will not be able to recoup the financial outlay for the satellite, thus decreasing the available worldwide communications links.
Proper selection of beam coverage, radiated RF power, and weight do not guarantee that the satellite services, also known as xe2x80x9cspace assets,xe2x80x9d are utilized in an efficient or complete manner. For example, the fact that a satellite transponder channel has enough radiated RF power supplied by an RF amplifier, and the satellite has a proper antenna to direct the transponder channel to a given area on the earth""s surface, does not guarantee full utilization of the transponder signal. The bandwidth of the signal must be reviewed, analyzed, and configured to fully utilize the transponder channel to maximize the usage of the space asset, i.e., the transponder channel.
Further, as the assets operating on satellite systems become saturated, a typical response by satellite operators is to launch more satellites into the constellation to provide more services. These responses are made without regard to space asset efficiency and/or whether the launch of additional satellites will be cost efficient in terms of being able to provide additional communications links. At times, the launch of additional satellites into a constellation will provide diminishing returns.
From the foregoing, it can be seen that there is a need in the art for techniques to review, analyze, and configure a satellite constellation to fully utilize the space assets of the satellite constellation. It can also be seen that there is a need in the art to provide a tool to determine the growth limit of a satellite constellation. It can also be seen that there is a need in the art to provide more complete utilization of space assets without dramatically increasing the cost of manufacturing and operating a satellite.
To overcome the limitations in the prior art described above, and to overcome other limitations that will become apparent upon reading and understanding the present specification, the present invention discloses methods for operating a satellite constellation at an increased efficiency operational point. One method comprises the steps of calculating the maximum number of communications signals that each satellite in the satellite constellation can generate, determining an operational constraint on each satellite, the operational constraint limiting the number of communications signals that each satellite can radiate substantially simultaneously, determining an operational space for each satellite wherein the operational space is defined using the operational constraint and the calculated number of signals, and using the operational space for each satellite in the constellation to determine the operational point for the constellation.
An object of the present invention is to provide techniques to review, analyze, and configure a satellite to fully utilize the space assets of the satellite. Another object of the present invention is to provide more complete utilization of space assets without dramatically increasing weight. Still another object of the present invention is to provide more complete utilization of space assets without dramatically increasing the cost of manufacturing and operating a satellite.